European Union finance ministers are to meet in in Brussels Tuesday to hammer out an agreement over how high banks should build their defenses against future financial shocks, with the U.K. running the risk of being isolated over who should set the height.

The EU's 27 members agree on the need to increase capital reserves of banks, following an international agreement called Basel III, which was negotiated by the world's largest economies to avoid another financial meltdown such as the one brought on by the collapse of U.S. investment bank Lehman Brothers in 2008.

But the U.K. wants national regulators to be able to set requirements significantly higher than those of the EU — a position opposed by almost all other EU members, who fear investors might then prefer UK banks and flee from those in other countries.

On his way into the meeting Tuesday morning, George Osborne, the British chancellor of the exchequer, was non-committal about the possibility of reaching an agreement.

"This is a time of considerable uncertainty in the eurozone economies," he said, referring to the 17 countries — the U.K. not among them — that use the euro currency. "And that uncertainty is undermining the entire European recovery. And I think we're reaching a point where we've got to make a decision to see the eurozone stand behind their currency. A very important part of that, of course, is strengthening the entire European banking system. And that is what we intend to do today."

Once enacted, Basel III would require lenders to increase their highest-quality capital — such as equity and cash reserves — gradually from 2 percent of the risky assets they hold to 7 percent by 2019. An additional 2.5 percent would have to be built up during good times. All members of the G-20 have agreed to implement Basel III; if the European Union succeeds, it would become the first entity to institute the new requirements.

The U.K. is arguing that, because national taxpayers have to bail out banks when they fail, national authorities should be able to set more stringent requirements to guard against such failures. A compromise proposal offered by the Danes, who hold the rotating presidency of the European Union, would allow national authorities some leeway to increase requirements beyond those called for in the Basel III agreement. That proposal has broad support — except, so far, from the U.K.

The finance ministers can approve the compromise proposal without British support, through what is known as qualified majority voting, in which member countries have different numbers of votes according to their populations. However, there is a tradition in the EU that changes that would affect an industry in a particular country — such as the banking sector in the U.K. — are not forced into effect over the objections of that country, and consensus is sought.

"I think there should be a unanimous decision on such an important issue," Swedish Finance Minister Anders Borg said on his way into the meeting.